This invention is directed to new and useful improvements in derricks and more particularly to an electrooptical remote control system for regulating and controlling the movable operating members of a derrick and remotely energizing other derrick accessories.
Derricks and the components thereof can usually be operated and controlled at a main control station on or near the base of the derrick. Many derricks also include remote work posts such as aerial work baskets that have an auxiliary control station for remotely operating the main controls. It is well known to transmit control signals from an auxiliary control station to a main control station through hydraulic or electrical signal transmission means. Known signal transmission means often include a separate signal transmission line corresponding to each derrick operating member and accessory that is being remotely controlled. Known derricks that incorporate a multitude of remotely controllable operating members and accessories generally require complex harnessing arrangements to support the separate signal transmission lines, and coding or other identification is usually needed to distinguish one signal transmission line from another. It is thus beneficial to provide a system for remote regulation and control of the operating members and accessories of a derrick wherein all remote control signals can be transmitted through the same signal transmission member regardless of the number of movable operating members and accessories being remotely controlled.
Among the several objects of the present invention may be noted the provision of a novel remote control system for a derrick wherein electrical control signals of differing frequencies that each correspond to a respective operating member or accessory of the derrick are produced at one location on the derrick and passed through the same signal transmission member to a second location on the derrick; a novel remote control system for a derrick wherein different operating members and accessories of a derrick can each be actuated by a different electrical control signal frequency; a novel control system for a derrick wherein a plurality of differing electrical control signal frequencies are each converted to light pulses of corresponding frequencies, all the light frequencies passing through a single light transmission member for detection and identification by a discriminator circuit; a novel remote control system for a derrick wherein a plurality of different control signal frequencies each corresponding to a different operating member or accessory of the derrick are produced at one location on the derrick and are optically transmissible through the same light transmission member to another location on the derrick, each frequency being individually detected by a discriminator network and directed to associate with a respective operating member or accessory of the derrick; a novel remote control system for a derrick wherein the rate and direction of movement of an operating member of the derrick can be regulated by producing a variable duty portion within a cycle of a given control signal frequency corresponding to that operating member i.e., a variable pulse duration; and a novel remote control system for a derrick wherein a plurality of distinctive driving signals corresponding to differing operating members and accessories of the derrick can sequentially actuate their associated operating members and accessories and maintain said operating members and accessories in substantially simultaneous operation. Other objects and features will be in part apparent and in part pointed out hereinafter.